The transmission of data between different stations is proliferating at an astonishing rate. However, the media such as cables for transmitting the data between the different stations is limited in the amount of data that can be transmitted at any instant. As the number of different data transmitted simultaneously between different pairs of stations increases at a rapid rate, the probabilities increase that the data received by any station will become jumbled so that the data intended to be received through a cable by the station will become lost in the noise created in the cable by the data transmitted at the same time to other stations.
Various systems and methods have been devised to isolate at each station the data transmitted in a cable to the station from the noise transmitted in the cable to other stations. For example, sequences of frequencies (designated as hopping frequencies) have been selected for the transmission of data to a station. The data is transmitted in successive packets at progressive frequencies in the sequence. The receiving station and the station transmitting the packets to the receiving station both know what the progressive frequencies are and in what packets data will be transmitted at the progressive frequencies from the transmitting station to the receiving station. By providing the hopping frequencies for the transmission of the successive packets, hopefully the receiving station will be able to isolate clearly, from the noise received by the receiving station, the data transmitted to the receiving station.
Providing the system of hopping frequencies has significantly helped, but has not resolved, the problem. A receiving station is often still unable to separate, from noise received by a receiving station, the signals transmitted to the receiving station from a transmitting station. Part of this has resulted from the rapidly increasing volume of signals transmitted at each instant through a medium such as a cable and from the inability of the receiving station to respond only to the signals received by it from the transmitting station and to disregard the rapidly increasing volume of extraneous signals received by the receiving station from other stations than the transmitting station.
Attempts have been made to resolve the problem discussed above. For example, the following articles set forth attempts to resolve the problems discussed above.                (1) El-Khamv S., “Matched Frequency Hopping (MFH) Signals For Slowly Fading Dispersive Channels”, IEEE Transactions on Vehicular Technology, Vol. 47, No. 1, February 1998.        (2) Sabbagh I., Appleby D., “Adaptive Slow Frequency-Hopping System for Hand Mobile Radio”, IEE Proceedings, Vol. 132, Pt. F. pp 375–383, August 1985.        (3) Pursley M., “Research in Spread—Spectrum Radio Systems and Network”, Final Report to U.S. Army Research Office, 15 Aug. 1993–30 Apr. 1995.        (4) Pursley M. and Gass J., “Tradeoff Between Frequency-Hop and Direct Sequence Signaling for Frequency Selective Fading Channels”, Conference Proceedings for MILCOM 96, pp 70–73, December 96.        